Solar Cell Characterization Using The IV Curve Method

By Zbigniew "ZB" Drozdowicz, Ph.D., Erik Haverkamp, and Allen Smith, Abet Technologies, Inc.

Research and development on solar cells is a rapidly growing area contributing to the "greener" earth future. Many different solar cell materials are investigated to find the "best" device possible. To characterize the devices, and to control the solar cell manufacturing process, reliable measurement techniques are required. Many measurement techniques have been developed during the past 40 years to characterize solar cells. In the electrical domain, common techniques are current voltage (IV curve), quantum efficiency, laser beam induced current, electroluminescence, and capacitance voltage measurements. All of these techniques have their own strengths, but a current voltage measurement system is one of the most critical tools providing information about a cell's efficiency. Typical components of such a system are shown below.

The current voltage method, commonly known as IV curve, is used to find the five most important parameters of a solar cell:

• Short-circuit current (Isc)
• Open-circuit voltage (Voc)
• Fill factor (FF)
• Maximum power (Pmax)
• Efficiency (n)